Math Is Fun Forum

Milenne

Guest

Reflex angles

Hi! I have been finding websites to find out the answer to this and finally, it came! Anyway, how can you find the reflex angles of angles that are also reflex? I know that this is a bit complicated to answer, but my math teacher said that this was a part of a year 4 math test but I am in year 8! Even my classmates said that this was so complicated.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Hi! I have been finding websites to find out the answer to this and finally, it came! Anyway, how can you find the reflex angles of angles that are also reflex? I know that this is a bit complicated to answer, but my math teacher said that this was a part of a year 4 math test but I am in year 8! Even my classmates said that this was so complicated.

I had also got this question but I was in year 7 and now I'm in year 11 but I am very sorry I had forgotten the answer but when I told the answer to my teacher, i got an A+ and I am now in Set One! If I remember, I will explain it to you.

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,384

Re: Reflex angles

Hi Milenne and jabah013.307,

Please see the link below.

Reflex angles.

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Hi Milenne and jabah013.307,

Please see the link below.

Reflex angles.

Hello,
Thank you for this link but how will it explain?
EDIT: It doesn't explain the problem that Milenne and I are having.

Last edited by jabah013.307 (2021-07-25 02:09:31)

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,876

Re: Reflex angles

Hi Milenne and jabah013.307,

Please supply a diagram of an example of the problem, as I can't visualise it.

Also, what is your understanding of a 'reflex angle'?

---

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Bob

Administrator

Registered: 2010-06-20

Posts: 10,619

Re: Reflex angles

Hi Milenne and jabah013.307

I too cannot figure out what you are after. 

jabah: from your Ip it looks like you're in the UK.  I've checked the government website and reflex angles are not in the year 4 programme of study.  Simple identification questions like " Is this angle acute, obtuse or reflex?" come in year 5.  Of course it's possible the US curriculum has this a year earlier but even so it's not a topic to get worried over.

Get a piece of paper and mark a point O as the centre of a circle and also put on a fixed point A. Now have a second point B that can freely roam around the circle.

If B is on top of A the angle AOB is zero.

If C is the point where COA = 90 then when B is between A and C the angle AOB will be acute (ie. less than 90)

If D is the point where AOD makes a straight line (the diameter of the circle) then any position for B between C and D make AOB on obtuse angle ie between 90 and 180.

If B moves even further around the circle then AOB will be reflex ie. over 180.

That is until B is once more on top of A.  We could call the angle AOB 360 in that case but it's the same as zero.  As B continues to rotate around the circle the angle goes over 360.  eg. 370.  But we don't have a special name for such angles as 370 looks the same as 10.

So the words acute, obtuse and reflex are just names given to different groups of angles.

On a protractor there are usually two scales, one running clockwise and the other anticlockwise.  So one way it's 0 to 180 and the other way it's 180 to 0.

This gives the user the option to measure an angle clockwise or anticlockwise.  You can get 360 protractors so you could measure a reflex angle with one of these.  But you don't really need such a protractor as it's easy enough to add 180 to your measurement.

how can you find the reflex angles of angles that are also reflex?

This question doesn't make sense.  Reflex is just a describing word (like heavy or blue but for a type of angle) so you cannot find the reflex angle of anything any more than you can find the 'heavy' of something or the 'blue' of something.

So it looks like we have a translation issue here, and that's not what you mean.  I googled reflex angles and there are loads of worksheets available.  So if you are having trouble putting up a diagram, how about giving us the link to a worksheet that has a similar problem.

At the moment that's the most help I can offer.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Hi Milenne and jabah013.307

I too cannot figure out what you are after. 

jabah: from your Ip it looks like you're in the UK.  I've checked the government website and reflex angles are not in the year 4 programme of study.  Simple identification questions like " Is this angle acute, obtuse or reflex?" come in year 5.  Of course it's possible the US curriculum has this a year earlier but even so it's not a topic to get worried over.

Get a piece of paper and mark a point O as the centre of a circle and also put on a fixed point A. Now have a second point B that can freely roam around the circle.

If B is on top of A the angle AOB is zero.

If C is the point where COA = 90 then when B is between A and C the angle AOB will be acute (ie. less than 90)

If D is the point where AOD makes a straight line (the diameter of the circle) then any position for B between C and D make AOB on obtuse angle ie between 90 and 180.

If B moves even further around the circle then AOB will be reflex ie. over 180.

That is until B is once more on top of A.  We could call the angle AOB 360 in that case but it's the same as zero.  As B continues to rotate around the circle the angle goes over 360.  eg. 370.  But we don't have a special name for such angles as 370 looks the same as 10.

So the words acute, obtuse and reflex are just names given to different groups of angles.

On a protractor there are usually two scales, one running clockwise and the other anticlockwise.  So one way it's 0 to 180 and the other way it's 180 to 0.

This gives the user the option to measure an angle clockwise or anticlockwise.  You can get 360 protractors so you could measure a reflex angle with one of these.  But you don't really need such a protractor as it's easy enough to add 180 to your measurement.

how can you find the reflex angles of angles that are also reflex?

This question doesn't make sense.  Reflex is just a describing word (like heavy or blue but for a type of angle) so you cannot find the reflex angle of anything any more than you can find the 'heavy' of something or the 'blue' of something.

So it looks like we have a translation issue here, and that's not what you mean.  I googled reflex angles and there are loads of worksheets available.  So if you are having trouble putting up a diagram, how about giving us the link to a worksheet that has a similar problem.

At the moment that's the most help I can offer.

Bob

But there is this app called Mathopolis and Maths Is Fun made it. In it, I checked the year 4 skills and there was a skill called 'Angle Naming' and it was even trickier than I thought the questions would be! Please check for yourself, as you may agree with me. It has all the angles and you have to name it or say which angle it is similar to.

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,876

Re: Reflex angles

Hi Milenne and jabah013.307,

But there is this app called Mathopolis and Maths Is Fun made it. In it, I checked the year 4 skills and there was a skill called 'Angle Naming' and it was even trickier than I thought the questions would be! Please check for yourself, as you may agree with me. It has all the angles and you have to name it or say which angle it is similar to.

The two images below are from MIF's Angles page that opens from the Angles - Acute, Obtuse,... link on the Mathopolis Angle naming page.

They also appear on MIF's Reflex Angles page that ganesh gave the link to.

Definition: A 'reflex angle' is more than 180° but less than 360°.

Both images are of a reflex angle (marked by a blue arc) and an obtuse angle, that together sum to 360°.

The first image includes the angle names in their respective sectors.

Unlike the first image, the second image doesn't name the two angles. The word 'reflex' is just the descriptive title for that image, which, on the two MIF pages, is part of a set of images (see third image below) featuring different types of angles. All images in the set are named in this fashion.

Maybe the placement of 'reflex' in the second image could be misread as indicating the existence of a reflex angle in both sectors...I don't know if this applies to your case of finding 'reflex angles of angles that are also reflex'.

Anyway, the first image correctly identifies the non-reflex angle (marked by an orange arc) as 'obtuse', which is also what the angle (no arc) in the corresponding sector of the second image is (despite the appearance of the word 'reflex' there).

EDIT: Here's the 'set of images' I referred to above:

Last edited by phrontister (2021-08-22 01:16:31)

---

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Bob

Administrator

Registered: 2010-06-20

Posts: 10,619

Re: Reflex angles

hi jabah013.307

I agree; the questions are tricky but if you get one wrong you get clear notes on what you should have done.  My advice is try all 10, then leave it a day and try them again.  I think you'll find they are easily on day 2 and you'll get more (all?) right.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Ok thank you Bob I will try my best to do so

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Hello but when I went to the skill, I pressed on an incorect answer (accidentaly!) and it just told me the correct answer and no explanations!

Last edited by jabah013.307 (2021-07-26 22:34:41)

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Hello but when I went to the skill, I pressed on an incorect answer (accidentaly!) and it just told me the correct answer and no explanations!

So how am I meant to answer all 10 of them without knowing how to work it out?

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,619

Re: Reflex angles

post the question and your answer here please.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

post the question and your answer here please.

Bob

I will have to send an image because there is a diagram shown in the question.

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

If the image does not show up, then I will tell you the question.

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,876

Re: Reflex angles

Hi jabah013.307,

Here's the image:

---

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Yes so how do you work this out?

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,876

Re: Reflex angles

This MIF page will help: Angles, which also opens from the Angles - Acute, Obtuse,... link on the Mathopolis Angle naming page.

In particular, look at the two sections near the bottom, headed 'Parts of an Angle' and 'How to Label Angles'.

Last edited by phrontister (2021-07-28 03:42:30)

---

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

jabah013.307

Member

From: Kingdom Of Jabah013.307

Registered: 2021-07-05

Posts: 165

Website

Re: Reflex angles

Thank you very much phrontister! I now understand very much now!

---

Quote Of The Month:
'Whether it's the best of times or the worst of times, it's the only time we've got.' - Art Buchwald.

ItsJustMilenne

Member

Registered: 2021-08-20

Posts: 6

Re: Reflex angles

Oh! All right then, thanks for the answer, phrontister!

---

ItsJustMilenne | Maybe an always active user? | And um...does likes vegetables count???